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ELECTRIC LAMP No. 255,305. Patented Mar. 21,1882.

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ELECTRIC LAMP.

No. 255,305. Patented Mar. 21,1882.

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kr/QW M UNITED STATES PATENT Orric' HIRAM S. MAXIM, OF BROOKLYN, ASSIGNOR TO THE UNITED STATES ELECTRIC LIGHTING COMPANY, OF NEIV YORK, N. Y.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 255,3(5, dated March 21, 1882.

Application filed August 4, 1881. (No model.)

To all whom it may concern:

Be it known that I, HIRAM S. l\lAXI1\1, of the city of Brooklyn, county of Kings, and State of New York, have invented certain new and useful Improvements in Electric Lamps, of which the following is a specification, reference being had to the drawings accompanying and forming a part thereof.

My invention relates to improvements in electric lamps in which the light is maintained by the separation of two carbon pencils or electrodes; and the objects of my invention are, first, to provide for a steady and continuous feeding together of the carbon points in exact proportion to the rate of their consumption; second, to bring the carbons instantly together when the current ceases to flow; third, to shunt those lamps out of the circuit in which the carbons have been consumed for a predetermined distance, or as far as is compatible with the safety of the lamp; fourth, to provide an adjustable and improved means of attaching the lower carbon to the lan'ip-frame; and, lastly, to improve the lamps as now used by the addition or substitution of certain novel features of construction, all of which will hereinafter be more fully set forth and claimed.

The above objects I attain by the devices illustrated in the accompanying drawings, where- Figure 1 is a view in elevation of theinterior of the lamp, showing the working portions of the feed mechanism, the lower part of the lamp and carbon-holder being illustrated partly in section; Fig. 2, a sectional view of the upper portion of Fig. 1, taken on line .1 or of Fig. 3; Fig. 3, a plan view of a portion of the feed mechanism; Fig. 4, an elevation of the retarding devices used with the feed-rollers; Fig. 5, a portion of the same in section; Fig. 6, a sectional view of an improved form of dash-pot to be used with the movable armature of the lamp. Figs. 7 and 8 are views in elevation and plan, respectively, of the devices for use with the carbon-holder for shunting the lamp out of circuit. Fi 9 is a sectional view, on line 3 y, of the feed-magnets and appurtenances.

In the several figures similar letters refer to corresponding parts.

A A A is the upper frame of the lamp, cast in one single piece of soft iron, prefe nbly in the form shownthat is to say, approximately that of the letter A, with the portion B corresponding to the cross widened out in disk form to serve as a base-plate for the case or cover B inclosing the feed-regulating devices. To the extremities of the frame A the side bars of the lamp are attached in the usual manner with insulating washers. The sides of the frame are formed parallel for asnitable distance above the cross-plate B, and considerably reduced in diameter, except at the points A A. The reduced portions are wound with coils O O of insulated wire of low resistance, the direction of winding being such as to form consequent poles of opposite polarity at the points A 1 when the iron extends out flush with the surface of the ('OllS, or slightly beyond them, to serve as polar faces. The poles A A are joined by a frame, 1), of brass or other nonmagnetic metal, between which is a soft-iron bar, E, branched to form a ring, E, at its center, and from which ring extend trunnions that serve as pivots for the bar.

On opposite ends of bar E aie wound coils F of fine insulated wire of high resistance, included in a shunt or derived circuit about the lamp, the direction of winding and connections with the main circuit being such as to produce in the ends of the bar or core E a polarity similar to that in the adjacent poles of the main magnets A A.

One of the trunnions or pivoting-points, c, from ring E is extended beyond the frame D, and to it is rigidly secured a lever, (7, connected at one end with the piston-rod of a small dash-pot, P, and at the other to the stationary base of the lamp by an adjustable tensionspring. To 0 is also fixed by a clam ping-screw, so that its position may be shifted, a sleeve, f, from which extends a spring-finger, c.

To the bar E is pivoted, at a point to one side of the middle, a link, u. G is a light rectangular t'rame, (shown in plan in Fi 3,) supported by the l nk or connecting-rod a, that is pivoted to it atone end. The other end of frame (r is prevented from dropping beyond a predetermined point by a suspended pin, 1), that passes through a hole in an extension, I), and is provided with an adjustable stop or head.

1 g are rollers on shafts journaled in opposite sides of frame Gr, one of which shafts,

ICO

as g, is extended beyond both bearings, and carries at one end a friction-disk, H,and at the other a retarding device, I-such as a rotary fan or other devices-presently to be described. On the periphery of this friction-disk H the spring-finger 0. carried by the trunnion c, bears, as shown in Fig. 1.

K is the carbon-holding rod, passing between the rollersg g, through the ring portion of pivoted core E, and through guides or a close-fitting aperture in the base B. The rollers g g are beveled off around their peripheries, and arojournaled at such a distance apart that when the frame G is tilted, as shown in Fig.2, they will bind in longitudinal grooves in the carbon-holder K; but when the frame is horizontal they willjust allow the holder to drop freely between them.

The shaft 9, as stated above, carries at one end a retarding device. This may consist, as stated, of a simple revolving fan. The device which I design to use, however, as being the best adapted for restricting the shalt g to a very slow and even motion is illustrated in Figs. at and 5. In these figures, L represents a light frame, and It R two dash-pots pivoted thereto. The frame L is intended to depend from the shaft 9, and is prevented from shifting its position by pins mm, which project up and pass through holes in the lower part of the frame from the stationary portion of the lamp. On the shaft 9 is fixed a disk, I, with which the two piston-rods r are connected by a single pin, '11. The shalt g, in revolving, therefore, encounters the force of the two pistons as they work up and down in dash-pots R and R. The resistance to rotation thusobtaincd will be nearly constant, and will restrict the movement of shaft g to an even and slow rotation.

' In Fig. 5 one of the dash-pots R R is shown in section. In Fig. 6 the dash-potP is shown also in section. In both cases they consist of a cylinder having a cover, 12, fitting tightly by a screw-joint, and a tube, 1;,let down from the cover 1) around the piston-rod nearly to the level of the liquid in the interior. With this construction thepiston rod is free to work without friction, the tube 1) being of somewhat greater diameter than the said rod, while the lamp may be placed in various positions or tipped without spilling the contained liquid.

The operation of the lamp is as follows: hen no current is flowing through the lamp the coils F and core E remain in the position shown in Fig. 1, they being caused to assume this position by the weightof frame G and the retarding devices carried thereby. When in this position frame G is horizontal andthc rollers or disks 9 g are notbinding the carbon rod K. This latter is therefore in its lowest position, and the carbons are in contact. When the current is completed through the lamp the main magnets bythe coilsCObecome strongly energized,and as but little current is nowflowing through coilsF the core E is attracted like an ordinary armature. The core E is therefore caused to assume a horizontal position. In doing this the frame G is tilted, the disks 9 9 caused to bind the carbon-carrier K, and spring 0 pressed against disk H. This prevents rollers g g from turning and raises the carboa carrier K, thus forming the are. As the arc increases in length the resistance of the lamp is increased. This causes more current to pass through coils F and increases the magnetism of core E until it neutralizes or overcomes the attraction of poles A A. The weight of the carbon carrier and the frame G now operates to tilt the core E against the tension of spring S and the lessened attraction of poles AA, a

too sudden movement being prevented by the dash-pot P. The tilting continues until the pressure of spring 0 is so much reduced that the disk H is permitted to revolve, the tendency to turn being imparted to it by roller 9 and shaft As the disk revolves, the retarding mechanism I is brought into play and restricts the speed of rotation, by this means permitting the carbon-carrier to descend with only a slow motion. As soon as the normal length of are has been reestablished by the descent of the holder the poles A A regain their original attractionandthccore E is again drawn up, and this operation is continued until the carbons are consumed.

Should the arc become interrupted for any cause, the only path left for the current would be through coils F, which, being of high resist ance, run the risk of being destroyed unless the carbons are instantly brought into contact again. This will be done as follows: On the interruption of the arc the core E would be tilted at once to its greatest angle from a horizontal line, so that the frame G- would by coming in contactwith the stop or pin Z) atoneenl be brought to a horizontal position. This, as has been set forth, allows the carbon-carrier to freely descend. As soon as the carbons are thus brought in contact the normal action of the lamp continues.

Another feature of my invention consists of an improved device for securing the lower carbon to the lamp-frame. This device, which is shown in section in Fig. 1, consists of a socket, M, provided with clamping-jaws, and ending in a solid portion, N, passing through the crossbar Q, and having a flange, m. The end of N is screw-threaded and a plate, '6, screwed thereon. S S are screws that pass through disk t, and whose points work in the rounded heads 8 s, that bear on the under side of bar Q. s is a spiral spring, held by flange m in a suitable seat in the cross-bar Q. The end of the carbon is clamped in socket M, and its vertical position is adjusted by means of screws S S, of which there should be at least three. The spring 8 serves to steady the holde and maintain a perfect contact for all positions of the same.

The devices connected with the above-do scribed lamp for shunting the same out of the circuit when the carbons are consumed are shown in Figs. 7 and 8. T T are two insulated screw-posts passing through base-plate B near the carbon-holder. T screws into a metal plate, t, bent up on opposite sides. (Shown in Fig. 8.) Between these two sides is pivoted a lever, V, and directly over the fulcrum is a compressed spiral *spring, 1;, connected with the lever and the plate t. It the lever V be tilted to one side or the other, the pressure of spring 12 is thrown off from the fulcrum and keeps the lever in its tilted position. The screw-post T ends in a stop, t, against which a small platinum button on leverVis arranged to come in contact. The two posts T T form the terminals of a normally-open shunt-circuit of low resistance, formed as shown in Fig. 2, by bringing of short lengths of wire from the main conductors. The end ot'leverVis pointed and projects into a slot in the carbon-carrier, so that the carrier descends without moving the lever until the end of the slot is reached. When this occurs the pointed end of the lever V is depressed, thus throwing the pressure of the spring off the center and closing the connection between the two posts T and T. By this means the current is shunted around the carbons through a path of low resistance, the shunt remaining closed until the end 1 of the lever is pulled down by hand. The length of the slot in the carbon-carrier determines the point to which the carbons are to be consumed, and may be varied as desired. Instead of a slot in the holder, a small slot in the base B may be made, through which a pin fixed in the carbon-holder at the desired point will pass and engage with the end of lever V.

As a means of preventing the operation of the cut-out I have shown a swinging arm, Y, having a hook on its end, which may be turned to surround the carbon-carrier and intercept the downward movement of the pointed end of the lever by fixing to the latter a projecting lug or stop, U. It may he often desirable to make use of this locking device in testing or experimenting with the lamp.

I would state that in this application I do not desire to cover broadly the idea of a magnet. in the main circuit, whose armature is wound with a conductor in a derived circuit of high resistance.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In an electric lamp, a frame of magnetic metal supporting the feed-regulating mechanism, the sides of said frame being provided with pole-pieces and wound with an insulated conductor forming part of the lamp-circuit, substantially in the manner set forth, to form the feed-regulating magnets.

2. In an electric lamp, the combination, with the side rods andconnecting-bar, of an upper supporting-fra me of magnetic metal, cast in one piece, the sides of which are provided with pole-pieces and wound with an insulated conductor forming a part of the lamp-circuit, substantially as and for the purpose set forth.

3. The combination of two electromagnetic cores, having coils included in the main or are circuit of an armature wound with coils forming part of a shunt-circuit of high resistance, and pivoted midway between the said cores, a gravitatingcarbon-holder, and mechanism connected with the pivoted armature and adapted to control the descent of the carbon-holder, substantially as set forth.

4. The combination, in an electric lamp, of parallel cores, having consequent poles A A" and coils O 0 included in the main or are circuit, armature E, pivoted between the said poles and having coils I forming part of a shunt about the lamp-carbonholding rod K, and mechanism connected with the pivoted armature and adapted to control the descent of the carbon-holder, as set forth.

5. The combination of pivoted armature E, link a, and frame G, having shafts carrying friction wheels journalcd therein, which are adapted to engage with the carbon-holder K, one of said shafts, g, being provided with a friction-disk, H, whose rotation is controlled bya detent, 0, carried by the armature E, substantially as set forth.

6. The combination of pivoted armature E,

connecting-link a, and frame G of shafts journaled therein and carrying friction disks which are adapted to engage with the carboncarrier K when the frame G is tilted, frictiondisk H, retarding mechanism I, and a springdetent, 0, carried by thearmature E and arranged to bear on the periphery of said disk, substantially as set forth. 7. The combination, with carbon-holder and rotary feed mechanism connected therewith, ot' a disk fixed to a shaft engaging with the said carbon-holder, and two or more pivoted dashpots, whose pistons are connected to the disk by the same crank-pin, as set forth.

8. The combination, in an electric lamp, with the carbon-holding rod, of a cut-out or switch consisting of a pivoted contactlever, V, insulatcd terminals T T, and a spiral spring, a, connected to the lever at a point directly above the fulcrum, as and for the purpose set forth.

9. The combination, with carbon-holding rod K, pivoted lever V, spring r, and insulated terminals T T, of a locking-lever, Y, adapted to be turned so as to prevent the tilting of lever V, as and for the purpose set forth.

10. In an electric lamp, the combination of a carbon-holder consisting of a stem, N, having a socket for the reception of the carbon flanges m, and a plate, I, carrying adjustingscrews, with the cross-bar 0, provided with a. socket containing a spiral spring, 8, as described.

In testimony whereof I have hereunto set my hand this 27th day of July, 1881.

HIRAM S. MAXIM.

Witnesses:

CLAYTON KNEELAND, PARKER W. PAGE. 

